Connecting to the ESP32
Please follow this guide from ESPHome : Physically Connecting to your Device
It is strongly recommended to backup the factory firmware. For this, we use Espressif [esptool] (https://docs.espressif.com/projects/esptool/en/latest/esp32/)
$ esptool.py --chip esp32 read_flash 0x00000 0x400000 flash_4M.bin